A federal judge determined Monday that the man accused of killing six in an Arizona shooting rampage is "getting better," further ruling that the suspect should continue to take anti-psychotic medications as his appeal works its way through the courts.

U.S. District Court Judge Larry Burns said in a motion issued Monday that there was a "substantial probability" that Jared Lee Loughner will be restored to competency and be able to stand trial for his role in a mass shooting in January outside a Tucson supermarket. He refused to alter Loughner's current mental health treatment plan, pointing to his observations that the suspect has improved in recent months.

"There is overwhelming evidence that the defendant is getting better, not the least of which is the noticeable improvement in his appearance, demeanor and behavior since he was last in court," the judge said in his six-page order.

Burns is based in Southern California, but is overseeing the case in part because one of the shooter's victims was Arizona-based federal Judge John Roll.

Loughner, 23, may face the death penalty if convicted in a shooting that also left 13 wounded, among them his purported target, U.S. Rep. Gabrielle Giffords. She has been undergoing intensive rehabilitation in Arizona and Texas since being shot in the head.

The suspect has been diagnosed as schizophrenic and has spent time on suicide watch while in custody and undergoing treatment at a federal hospital in Springfield, Missouri.

In May, a federal appeals court cleared the way for him to be forcibly medicated, over the objections of Loughner and his attorney.

A hearing five days ago addressed those objections. During it, both the judge and mental health experts noted that Loughner was able to sit calmly during the hours-long proceeding, court sources said. He had been removed from a courtroom in May after an outburst, reported CNN affiliate KGUN.

Prosecutors have written in court documents that Loughner has expressed "regret for the circumstances that led to his arrest." When he was asked whether he thought about harming himself, he said, "I want to die. Give me the injection. Kill me now," the documents said.

The defense team argues the state has failed to prove Loughner's condition will improve enough for him to stand trial.

Based in large part on their assessment of the suspect's improvement under his current medical regimen -- including the prescribed medications -- Burns decided it was best not to change Loughner's treatment.

"The testimony of (Pietz and Ballenger) established the likelihood and substantial probability that the defendant will continue to get better and can be restored to competency to stand trial in four months time," the judge wrote.